China with the world's largest population is facing a potential devastation of the rapidly growing HIV epidemic. Since the multicultural and multiethnic characteristics accompany wide geographic and socio-demographic variations, there is much that is unknown about the scope of HIV risk. Accurate information is a key to any success of disease prevention programs; there is a need to improve the estimates of HIV prevalence and to provide accurate information for prevention. The specific aims of this project are 1) to evaluate critically the quality and the generalizability of data from different sources in selected provinces. 2) to assess the validity of the new Estimation and Projection Package and Workbook Program of UNAIDS/WHO in estimating short-term projections of selected provinces. 3) to improve estimates of the true prevalence of the HIV/AIDS epidemic in selected provinces using the best sources of seroprevalence, surveillance, and modeled data. 4) to assess the epidemic growth rate in the provinces studied and guide the China CDC as to where interventions are most urgently needed. We propose to conduct study over a 2 year period that will be a collaborative effort between China CDC and a US university, which will be complementary to that of WHO, UNAIDS, and USA CDC through China CDC. In first year, we will estimate three selected provinces by synthesizing the results from several different data sources and three statistical estimate procedures. The estimates of HIV prevalence will be made by synthesizing the estimates from three different procedures followed by a comprehensive evaluation/analysis of relevant epidemiologic data and major potential bias elimination. The second year estimation and projection will base on the previous estimate, the updated software and newly available database and more understanding of the variety of parameters and distributions, such as the time of infection, the onset of detectable antibodies, therapeutic benefits, prevention effects, etc. We intend to use the findings to help the China CDC establishing a better estimation model for HIV/AIDS. [unreadable] [unreadable] [unreadable]